Wireless-telephone system



Jan. ,27, 1925. 1,524,413

M. W. STERNS WIRELES S TELEPHONE SYSTEM Filed Jan. 28A 1920 3 Sheets-Sheet l l .l- E 20 /2 5 im '6 v il? /hl- 9 :D y 22 HAMM/1 l 2/ /9 E 2f -E 77- 24 /4 Jan. 27, 925 1,524,413

. M. W.-STERNS ,WIRELESS TELEPHONE SYSTEM Filed Jan. 28. 1920 s sheets-sheet 2 Jan. 27, i925. 1,524,413

M. W. STERNS WIRELESS TELEPHONE SYSTEM Filed Jan. 28- 1920 3 Sheets-Sheet 5 HHN.

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Patented Jan. 27, 1,925.

UNITEDy STATES 'MORTON' W. STERNS, OF NEW YORK, N. Y.

WIRELESS-TELEPHON E SYSTEM.

Application led January 28, 1920. Serial No. 354,611.

To all 'whom it may concern.

Be it known that I, MonToN W. STERNS, a citizen ofthe United siding at New York, N. Y'., have invented a new and useful Wireless Telephone System, of which the following is a specification.

The main vobject, of my invention is to provide a simple apparatus and system for wireless telephony Which can be used both for sending and receiving at the same time.

Another object is to provide apparatus which is simple and compact and inexpensive and which can be used for transmitting or receiving, or both. f

Another object is to obtain a maximum power effect with the least possible apparatus and at a minimum of cost.

Another object is t-o utilize 'the same tube or tubes both for transmission and reception.

In its preferred form, the invention contemplates' the use of a three electrode valve or tube with a telephone transmitter arranged between the grid and filament circuits and a telephone receiver arrangedbetween the plate and filament circuit. The circuits are so related to a grounded aerial or to a loop that messages may be simultaneously sent and received. Signalling devices may be employed for undamped or damped signals. Where more power is required a number of tubes may be used with their elements in parallel.

Fig. 1 is a diagram of one form of apparatus embodying the improvements of my invention and showing a battery as the power source and a single tube..

Fig. 2 is a diagrammatic view of a complete system embodying a D. C. generator with a commutator filter, a plurality of valves or tubes, and a combined telephone and buzzer transmitter.

Fig. 3 is a diagrammatic view of another modification showing the telephone receiver connected directly in the power circuit which is of the battery type and a variable grid leak independent of the telephone transmitter transformer.

Fig. 4 is a diagram of another modification showing the transmitter inserted .directly in the aerial circuit.

U Fig. 5 is a diagram of another modification showing inductive coupling between the plate and 'd circuits. f

Fig. 6 s ows another yform of inductive coup ing States of America, re-

Fig. 7 shows a capacitative feed back and conductive coupling to the antenna.

Figs. 8 and 9 show other forms of inductive coupling to antenna and loop respectively.

In the arrangement shown-in Fig. 1, the -grounded aerial 5 contains a tuning inductance 6 and capacity 7.

The power circuit contains the source of current such as battery 8 which is connected by leads 9 and 10 to the aerial on opposite sides of the condenser 7. A telephone transformer is coupled to the lead 9 either directly or through an amplifier. In this case Ythe telephone transformer 11 has its primary in the battery circuit and its second` ary in the circuit of the telephone receiver 12.

The tube or valve 14 of any suitable type has a heating filament 15 with the local battery 16 and preferably an adjustable resistance 17. This filament circuit is connected by lead 18 to the aerial below the condenser 7.

rlhe anodefor ed by lea-d 20 to inductance.L

The grid or control element 21 is connected by lead 22 to the aerial above the condenser 7 but with a condenser 23 interposed and a grid leak resistance 24 connected to the filament circuit *to maintain a proper negative grid potential.

The grid leak resistance 24 may be one winding of a transformer having its primary 25 in circuit with a telephone transplate element 19 is connectthe aerial above the tuning mittel' 26.

Instead of using the grid leak 24 as a part o-f the transformer, a. separate coilv24,r may be used in conjunction [with the coil 25 as shown in Fig. 2. A separate grid leak resistance is necessary however where the resistance of the secondary of the transformer is too high to keep the grid negative.

When considerable powers are used, lseveral tubes or valves 14 and 14 may be employed as shown in Fig. 2 with their in parallel, that is, the

tive elements placed filaments are connected together and to the aerial below the tuning condenser, the anode plates are connected together and to the aerial above the tuning inductance, and the grids are connected together and to the aerial 4between the inductance and capacity elements of the aerial.

When a D. C. generator 8', as shown in in the power circuit, and condensers 2828 so as to minimize the commutator hum.

In the transmitting circuit of Fig. 2, I have shown a telephone transmitter 26 and la buzzer 29 in (parallel, and-I have provided switches 30 an 3l so that either the human voice or buzzer modulated signals may be transmitted. y By providing a switch in the filament lead 18, undarnpedjor' continuous wave signals .may be transmitted. By using normally closed spring contacts at 32 and normally opened contacts atBl, an ordinar telephone jack' and signalling key may be employed for use interchangeably at 32 or 31.' The tone of the signa-l transmitted from 31 will of course depend upon the frequency of the buzzer 29. When the switch 30 is closed and with the switch 31 open, speech directed at the transmitter 26 will be transmitted in the form of voice modulated electromagnetic waves. A

When smaller powers are used, the' receiver such as 12 may be connected directly in the circuit with the battery 8, as shown in Figs. Sand 4. I

he grid leak resistance 24 may be adjustable, if desired, `as indicated in Figs. 3

and 4.

A very simple form of arrangement is l shown in Fig. 4 where the transmitter 26 is shown connected directly in the aerial circuit. While this is satisfactory for small currents of sav one ampere or less, the transmitter is likely to become inoperative very quickly with higher power.

In designing the apparatus for proper modulation, the impedance of the secondary of the modulation transformer or induction coil should equal the input impedance of the tubeor tubes or the impedance between the grid and the filament. Furthermore, the impedance of the primary of they-transformer should equal the impedance of the transmitter, buzzer or other alternat'ng current source. The ratio of the primary to the secondary should be large so as to impress a high potential on the grid. On the other "hand, in the power circuit the impedance of the'primary should equal the impedance of the circuit in which it is inserted, and the impedance of the secondary. should erilial the impedance of the circuit into w ich it feeds such as a receiver or amplifying device. A strong D. C. which supplies power to the plate-circuit will not aifect the receiving devlce, but any weak A. C. eifect such as received signals or .your own voice` in the transmitter will aifect the receiving device.

By the foregoing invention it is possible to simultaneously transmit and receive on the same aerial and with the same wave vdenser may be direct to the inductance.

length and the same tube without the use of switches.

In case Station A wishes to speak telephonically with station B, station A will say, Hello B, Hello B, A calling, A calling, answer please. Station B on hearing A will tune to As wave length automatically as that is the ppint of loudest and clearest speech. If B now speaks to A, A will hear him, as he is tuned to the same wave length as B, due to the previous operations. It is evident therefore that A can break in on B, or vice Versa, at any instant and ask for a repeat in case of misunderstanding or for any1 other purpose and without throwing any switches. This circuit will therefore give all the advantages of an ordinary land line telephone with the added advantage of the peculiarly clear speech which is a well known advantage of the radio phone.

The connections of the filament and plate to the aerial may be transposed but in any case the positive of the battery 8 or generator 8 should be connected to the plate. The plate and grid connections to the aerial may also be transposed. The receiving dcvice may be inserted in or coupled with the negative lead of battery 8 or generator 8. The connection to the aerial above the clclie grid may be inductively coupled to thc'aerial instead of directly.

In the arrangement shown in Fig. 5, the grid and plate are inductively coupled through the coils 6 and 6', but the transmitter and receiver are connected with the grid and power circuits as above described.

In Fig. 6 both the grid and filament circuits are inductively coupled with the aerial inductance by the coils 35 and 36 respectively, and the receiver is connected between the plate and power source.

In Fig. 7 two condensers 7 and 7 are arranged in the aerial circuit. The filament is connected between these two ,condensers by the lead 18 and the grid and plate are connected on opposite sides of the condensers. The transmitter is connected as before between the grid and filamentcircuits and the receiver is connected in thepower circuit between the filament and plate circuits.

In the arrangement of Fig. 8, the transmitting and receiving circuits are inductively coupled with thc aerial by means of In the arrangement of Fig. 9, I have shown a loop 40 in place of the aerial, with atuning coil and capacity inductively coupled through thev coil 41 with the transmitting and receiving circuits In this case there is variable capacity 42 connected between the grid and plate circuits. This arrangement also requires condensers 43 and 44 connected substantially as in the arrangement of Figs. 7 and 8. Of course the telephone instruments may be inserted directly powers without the 1n the circuits for low interposition of transformers.

It should be understood that any of the circuit arrangements may use a loop antenna such as shown in Fig. 9 in place of the grounded aerial.

I claim:

1. In a wireless telephone system, the combination of a grounded aerial containing a tuningF inductance and condenser, a power circuit connected to said aerial and including a receiving device, a three electrode valve having a 1'ilan.ient,`a plate and a grid connected to said aerial, said plate being connected directly to said'aerial, a condenser in the grid'circuit, a grid leak resistance connecting the grid circuit and the iilament circuit, and a telephone transmitter inductively connected with the grid and filament circuits.

2. In a wireless telephone system, an aerial including an inductance and a capacity, a power circuit including a receiving device and connected on opposite sides of said capacity, a three element tube having its filament circuit connected on one side of said capacity, its grid connected between said inductance and said capacity and itsplate connected on the opposite side of said inducti ance, and a modulating device inductively connected between the cuits.

3. In a wireless telephone system, the combination of a grounded aerial, a power circuit connected to said aerial and including the primary of a receivingldevice, a three electrode valvehaving a ament, a plate grid and lament cirand a grid connected to said aerial, a con-- denser in the grid circuit, a grid leak resistance connected to the grid circuit between the grid and said `condenser and connected to the lilament circuit, and a telephone transmitter` inductively connected with the grid and filament circuits.l

4. 'In a wireless telephone system, an inductance and a capacity, a power circuit including the primary of a receiving device and connected on opposite sides of said capacity, a three element tube having its lament circuit connected on one side of said capacity, its grid connected between said inductance and said capacity and its plate connected on'the opposite side of said inductance, and a modulating device inductively connected between the grid and filament circuits. l a f 5. In a wireless telephone system,the combination of a tuning inductance and condenser, a power circuit connected thereto and including a receiving device, a three Y electrode valve h ving a filament aplate and a'grid connec ed to said circult, a con- ,ins a the secondary-of the transformer circuit, a grid leak resistance connecte to the grid circuit'between the grid and Said condenser and connected to the filament circuit, and a telephone transmitter connected-with the grid and filament circuits.

6. In a wireless telephone system, an aerial including an inductance and a capacity, a power circuit connected on opposite sides of said capacity, a telephone receiver coupled to said power circuit, a. three element tube having its filamentcircuit connected on one side ot' said capacity, its grid connected between sajd inductance and said capacity and its plate connected on the opposite side of said inductance, and a modulating device including a transmitter inductively connected between the grid and filament circuits.

7. In a signaling system, an aerial including a variable inductance and a variable capacity, ay three-element tube having a plate directly connected to the aerial and a lilament directly connected tof the aerial and a grid having a capacity connection to the aerial, a transmitting device inductively connected between the grid and filament, a grid leak between the grid and filament, and a source of direct current connected between the plate and filament.

8. In a signaling system, an aerial includ variable induct-ance and a. variable capacity, a plate directly connected to the aeriah'avfilament directly connected to the aerial, a grid connected between the inductance and capacity, a source of ldirect current between the iilament and plate and a receiving device inductively coupled thereto,

d enser in the gril` of the plate circuit, and the impedance of the secondary being equal to the impedance of the receiving device.

9. In a wireless telephone system, the combination of a grounded aerial containing a tuning inductance and condenser, a three electrode power tube having a filament, a plate and a grid all connected toy said aerial, a condenser in the grid circuit, a grid leak resistance connecting ithe grid circuit and the filament circuit, said filament being Vconnected to the low potential end of said aerial, a telephone transmitter and a transformer connecting the transmitter with the grid and filament circuits, the impedance of being equal to the input impedance of the'tube.

10. In a wireless telephone system, an inductance and a capacity in series, a power circuit including a choke coil and connect-ed on opposite sides of said capacity, a three element tube having its filament circuit connected on the low potential side of said capacity, its grid connected between said inductance and said capacity and its plate connected 'on the opposite side of said inconnecting the grid circuit and the filament circuit, a telephone transmitter inductively connected with the grid and filament circuits of said'tube, said filament being connected to the low potential side of said radiating circuit the impedance of the secondary of the inductive coupling being equal to the input impedance of the tube.

12. In a wireless telephonesystem, an inductance and a capacity, a power circuit including a power source and achoke coil and connected on opposite sides of said capacity, a three element tube hav-ing its filament circuit connected to the low potential side of said capacity, its gridV connected between said inductance and said capacity and its plate connected on the oppoosite side'of said inducta'nce, and a modulating device inductively coupled betweenv the` grid and filament of said tube, the impedance of the secondary of the inductive coupling being equal to .the input impedance of the tube, and the impedanceof the primary being equal to the impedance of the modulating device. c

13. In a wireless system for simultaneous rece tion and transmission, an aerial including inductance and capacity, a threeelement emission device having a filament,

an anode, and a gridconnected to said aerial,

impedance between the a source of direct current'connected to the aerial, a transmitting 'device inductively coupled. between the grid and filament, a receiving device inductivelyc coupled to the plate circuit, the impedance of the transmitter being substantially equal to the impedance of the primary of its inductive coupling, and the impedance of the secondary induetive coupling beingv equal to the "d and filament, the impedance`of the receiving device being substantially equal to the impedance of the secondary of its inductive coupling, andthe impedance of the secondary inductive coupling being substantially equal to the impedance of the late circuit. i 14. In a wire ess telephone system, a reception and transmission circuit, an oscillation device connected thereto and having an electron emitting element, a receiving element'and a control element, a modulation.r

emitting element and the control element and with an impedance equal to the in utl impedance vof the oscillation device, an' a resistance in parallel with said secondary. 16. In a wireless telephone system, an electron emitting element, a receivin element, a controlling element, a modu ation transformer having its secondary connected across the emitting and control elements, the impedance ofthe secondary of the transformer being equal to the impedance between the 'control and emitting elements, an'd a resistance in parallel with said secondary.

17. In a wireless'set, an aerial, a three element tube having a plate directly connected to the aerial, a filament circuit directly connected to the aerial, and a control element connected to the aerial, a transmitter connectedv in the grid circuit, and a. receiving device connected in the plate circuit.

18. In a Lwireless telephone set for simultaneous transmission and reception, a radiating aerial, a ower circuit connected to said aerial and including the primary of a telephone receiver, an oscillation device connected with said power circuit and having an electron emitting element, a receiving element and a control element, a modulation telephone transformer having its secondary connected between said emitting and control elements andd with an im ance equal to the input impedance of tie oscillation device.`

19. In a wireless set for simultaneous transmission an'd reception, a radiating aerial tin element, a receiving element and a contro element, said receiving element bein directly connected with said aerial, sai emitting element being directly connected `with said aerial, said control element being an oscillation device having an emitconnected with said aerial, a telephone trans- `rnitter connected to modify the radiations for said aerial and a telephone receivin device connected in the circuit with said receiving element.

MORTON W. STERNS. 

